Refers to the party that borrows money, rents property, or receives a loan. The context determines whether it means a financial debtor or a tenant.
The bank checks the borrower's credit.
The tenant for this apartment hasn't been decided yet.
Standard spelling; the okurigana り makes the reading clear.
Less common variant without okurigana; still seen but 借り手 is preferred.
Compound of 借り (kari, 'borrowing', the continuative form of 借りる) + 手 (te, 'person' in this context).